RECOVERY OF CAPROLACTAM FROM NYLON 6 OLIGOMERS

摘要

The recovery of caprolactam (I) from the concd. wash water of nylon 6 chips is carried out by (a) feeding the concn. wash water into a wiper-film evaporator operated at 200 - 300≦̸C and 10 - 250 torr to obtain an overhead stream of H2O and (I) and a bottom stream of (I) and cyclic oligomers, and recovering (I) from the overhead stream. The bottom stream is fed into a depolymerization kettle at 230 - 290≦̸C and contacted with superheated steam to depolymerize cyclic oligomers and strip off (I).